My pH meter was acting up badly; and it wasn’t that old. It would not equilibrate, but kept jumping around to wild numbers. I thought I would have to replace it, or at least the probe. Then one day a glob of solids fell out of the tip, and it’s been working quite well since then. So, How does one keep that delicate tip clean, without damaging it? I have never let it dry out, and I’ve tried using a cotton swab to clean it - but it’s very difficult to get anything into that restricted area for a thorough cleaning. Suggestions?